Static electricity is likely to be generated in the processes of manufacturing, assembling, testing, storing, or transporting electronic components. Moreover, static electricity can also accumulate in the human body, testing instruments, storing devices, and even in the electronic components themselves. When a human body, a testing instrument, or a storing device contacts an electronic component, ESD is liable to occur. When this happens, it can seriously damage or even destroy the electronic component. Therefore, an ESD protection device needs to be installed in various electronic components.
FIG. 3 is an abbreviated circuit diagram of a conventional liquid crystal display (LCD). The LCD 1 includes a plurality of ESD protection devices 10, a first common electrode 141, a second common electrode 142, a third common electrode 143, a plurality of scan lines 12 parallel to each other, a plurality of data lines 13 parallel to each other. The scan lines 12 are perpendicular to the data lines 13. Each scan line 12 is connected to the first common electrode 141 via an ESD protection device 10, and is also connected to the second common electrode 142 via another ESD protection device 10. Each data line 13 is connected to the third common electrode 143 via an ESD protection device 10.
FIG. 4 is a circuit diagram of one of the ESD protection devices 10. The ESD protection device 10 is connected between a first conductor line 101 and a second conductor line 102. The first conductor line 101 may be one of the scan lines 12 when the second conductor line 102 is one of the first common electrode 141 and the second common electrode 142. Alternatively, the first conductor line 101 may be one of the data lines 13 when the second conductor line 102 is the third common electrode 143. The ESD protection device 10 includes a first transistor 110, a second transistor 120, and a third transistor 130. A gate electrode of the first transistor 110 is connected to the first conductor line 101, and a drain electrode of the first transistor 110 is connected to the first conductor line 101. Further, a source electrode of the first transistor 110 is connected to a gate electrode of the third transistor 130. A gate electrode of the second transistor 120 is connected to the second conductor line 102, and a drain electrode of the second transistor 120 is connected to the second conductor line 102. Further, a source electrode of the second transistor 120 is connected to the gate electrode of the third transistor 130. A drain electrode of the third transistor 130 is connected to the second conductor line 102, and a source electrode of the third transistor 130 is connected to the first conductor line 101.
When a voltage difference between the first conductor line 101 and the second conductor line 102 is larger than a setting voltage of the first transistor 110 or the second transistor 120, the third transistor 130 is turned on. Accordingly, ESD occurs via the activated third transistor 130.
However, when the ESD protection device 10 discharges, users generally cannot perceive the occurrence of the discharge and cannot ascertain the time of discharge. The reason is that the ESD protection device 10 has no means for alerting or recording the occurrence of ESD.
What is needed, therefore, is an ESD protection device and a method of fabricating the ESD protection device which can overcome the above-described deficiencies.